I agree with epoh--at least that worked wonders for us when DD was younger. It was important to have both the rules and consequences be clear in advance, to give one reminder (as a chance for the kid to make the correct choice) and then to promptly follow through if the behavior doesn't stop. For awhile we gave a 'count' for bad behavior and if our DD got up to three counts, no dessert (bad, I know, but that was the only thing that worked with her).
Another technique is that if the kid is not using a toy/material properly, it becomes 'unavailable' for awhile (that is, you take it away); if they are otherwise behaving, you can have them try it again, but if they go back to the inappropriate use, it is 'unavailable' for longer (like until tomorrow, or until next week). Positive reinforcement can sound like "I will know you are ready to use the paint when you keep it on the paper." Hang in there; your DD sounds very persistent, but hopefully you will be able to make some progress. Good luck!
